Is my 1989 Force 85 sitting too low?

thimsllib

Seaman
Joined
Aug 7, 2009
Messages
50
Does anybody know if there was a ?long shaft? 85hp Force? The motor on my 1700 Capri seems to be too low in relation to the hull. I am thinking that this may be contributing to the low top end speed. I have always thought that the cavitation plate should be more or less even with the bottom of the ?v? on the hull. Also, the motor would have to be raised on the transom in order to correct this, is anyone?s 85HP Force transom mount not resting on the top of the transom?
 

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Re: Is my 1989 Force 85 sitting too low?

AFAIK, the 85 HP only came with a 20" shaft. Someone may have swapped it for 25" parts from a 125 HP. How far below the hull is the cavitation plate?

My motor sits directly on the top of the transom. The original motor, without tilt & trim, sat on top of a wooden shim about 1/4" thick.
 

thimsllib

Seaman
Joined
Aug 7, 2009
Messages
50
Re: Is my 1989 Force 85 sitting too low?

NYBo - Thanks for the info. Are you saying when you bought your 88 1700, the motor did not come with the power T/T, but it had a shim on the transom? Now you have power T/T and no longer need the shim?

I bought my boat 3 months ago and have been trying to get it to run right all summer. Finally got most of the mechanical issues ironed out (still some work to do) and I've been trying to figure out why my top end speed is only about 28MPH. I know the boat is heavy because it's water logged, but then it hit me.... when I had the boat on the trailor in the driveway, I had to have the bow lowered in order to put the motor down. My motor does not have power T/T and does not have a shim on the transom. I wonder if it should be shimmed or if a previous owner swapped out the lower unit for a 125 and/or if it should be shimmed?
 

john from md

Commander
Joined
Apr 13, 2008
Messages
2,184
Re: Is my 1989 Force 85 sitting too low?

Take a straight edge and run it along the top of your cav plate on the engine. It should hit at the bottom of the keel or slightly above it.

John
 

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Re: Is my 1989 Force 85 sitting too low?

NYBo - Thanks for the info. Are you saying when you bought your 88 1700, the motor did not come with the power T/T, but it had a shim on the transom? Now you have power T/T and no longer need the shim?
Correct. The original '88 motor did not have power tilt & trim, and sat on a thin shim on top of the transom. I replaced it with an '87 with power t&t that I got off eBay.The mounting holes lined up only if I removed the shim.
 

thimsllib

Seaman
Joined
Aug 7, 2009
Messages
50
Re: Is my 1989 Force 85 sitting too low?

It's hard to tell at this point if the cav plate is lower than the bottom of the keel because it's still in the water, but I'm pretty sure it is. I can clearly see that the motor mount bolts are not through the original holes. There are 2 old holes just slightly above the 2 existing holes. At one point this motor sat about a 1/2 inch high than it is now. I'll tell you, the prior owner of this boat really did her in. it's been a long road getting her back to life, but I'm almost there.
 
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